STM32 SPI 主模式下配置(神州三号开发板spi.c解析上)

#include "spi.h"

#include <STM32F10X_SPI.h>
#include <STM32F10X_GPIO.h>
#include <STM32F10X_RCC.h>//包含头文件


 
//串行外设接口SPI的初始化，SPI配置成主模式  
//本例程选用SPI1对W25X16进行读写操作，对SPI1进行初始化
void SPIx_Init(void)
{
    /*定义结构体，下面NSS配置时也要用到GPIO所以这里一起定义*/
SPI_InitTypeDef  SPI_InitStructure;
GPIO_InitTypeDef GPIO_InitStructure;

/* 使能 SPI1 & GPIOA 时钟 */
         RCC_APB2PeriphClockCmd(RCC_APB2Periph_SPI1|RCC_APB2Periph_AFIO, ENABLE);

/* Configure SPI1 pins: NSS, SCK, MISO and MOSI */
         GPIO_InitStructure.GPIO_Pin = GPIO_Pin_5 | GPIO_Pin_6 | GPIO_Pin_7;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
GPIO_Init(GPIOA, &GPIO_InitStructure);

//SPI1 NSS for   W25X16                   
         GPIO_InitStructure.GPIO_Pin = GPIO_Pin_4;
         GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
         GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;
         GPIO_Init(GPIOC, &GPIO_InitStructure);

GPIO_SetBits(GPIOC, GPIO_Pin_4);

    //SPI1 NSS for Ethernet
          GPIO_InitStructure.GPIO_Pin = GPIO_Pin_4;
          GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
          GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;
          GPIO_Init(GPIOA, &GPIO_InitStructure);

GPIO_SetBits(GPIOA, GPIO_Pin_4);  

/* SPI1 configuration */
          SPI_InitStructure.SPI_Direction = SPI_Direction_2Lines_FullDuplex; //SPI1设置为两线全双工
SPI_InitStructure.SPI_Mode = SPI_Mode_Master;                    //设置SPI1为主模式
SPI_InitStructure.SPI_DataSize = SPI_DataSize_8b;                  //SPI发送接收8位帧结构
SPI_InitStructure.SPI_CPOL = SPI_CPOL_High;                //串行时钟在不操作时，时钟为高电平
SPI_InitStructure.SPI_CPHA = SPI_CPHA_2Edge;                //第二个时钟沿开始采样数据
SPI_InitStructure.SPI_NSS = SPI_NSS_Soft;                //NSS信号由软件（使用SSI位）管理
SPI_InitStructure.SPI_BaudRatePrescaler = SPI_BaudRatePrescaler_8; //定义波特率预分频的值:波特率预分频值为8
SPI_InitStructure.SPI_FirstBit = SPI_FirstBit_MSB;    //数据传输从MSB位开始
SPI_InitStructure.SPI_CRCPolynomial = 7;    //CRC值计算的多项式
SPI_Init(SPI1, &SPI_InitStructure);
/* Enable SPI1  */
SPI_Cmd(SPI1, ENABLE);   //使能SPI1外设
}